000161051 001__ 161051
000161051 005__ 20251017144600.0
000161051 0247_ $$2doi$$a10.1016/j.ymgme.2025.109150
000161051 0248_ $$2sideral$$a144274
000161051 037__ $$aART-2025-144274
000161051 041__ $$aeng
000161051 100__ $$aLongo, Lisa
000161051 245__ $$aMissense mutations in MMACHC protein from cblC disease affect its conformational stability and vitamin B12-binding activity: The example of R161Q mutation
000161051 260__ $$c2025
000161051 5060_ $$aAccess copy available to the general public$$fUnrestricted
000161051 5203_ $$aMMACHC protein plays a crucial role in the metabolism of vitamin B12 (cobalamin, Cbl) by catalyzing its conversion into the active forms adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl), which serve as essential cofactors in key cellular reactions. Mutations in the gene encoding MMACHC lead to the rare metabolic disorder known as methylmalonic aciduria and homocystinuria, cblC type. This condition predominantly affects children and is characterized by cardiovascular dysfunction, intellectual disability, and a severe form of maculopathy. The most common missense mutation, R161Q, impairs enzymatic activity despite not being directly involved in cobalamin binding. Here, using a comprehensive set of biophysical techniques, we demonstrate that this pathogenic variant compromises MMACHC structural stability, alters the thermal unfolding cooperativity and pathway, as well as the populations of conformational intermediates. Moreover, we show that the R161Q mutation decreases AdoCbl binding affinity and impairs the protein's ability to form homodimers, which are supposed to have a functional role. A partial recovery in protein activity upon treatment with betaine, an osmolyte known for its stabilizing effect on proteins, was observed. This suggests a direct correlation between the energetics of MMACHC thermal unfolding and its functional activity. These findings contribute to a deeper understanding of the molecular mechanisms underlying MMACHC function and open avenues for potential therapeutic interventions.
000161051 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttps://creativecommons.org/licenses/by/4.0/deed.es
000161051 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000161051 700__ $$aRandazzo, Loredana
000161051 700__ $$aBollati, Michela
000161051 700__ $$aCarrotta, Rita
000161051 700__ $$aCosta, Maria Assunta
000161051 700__ $$aDe Rosa, Matteo
000161051 700__ $$aMangione, Maria Rosalia
000161051 700__ $$aMartorana, Vincenzo
000161051 700__ $$aCulletta, Giulia
000161051 700__ $$aTutone, Marco
000161051 700__ $$aMari, Eleonora
000161051 700__ $$aOrtore, Maria Grazia
000161051 700__ $$aGarcia-Franco, Paula M.
000161051 700__ $$0(orcid)0000-0001-5702-4538$$aVelazquez-Campoy, Adrian$$uUniversidad de Zaragoza
000161051 700__ $$aPassantino, Rosa
000161051 700__ $$aVilasi, Silvia
000161051 7102_ $$11002$$2060$$aUniversidad de Zaragoza$$bDpto. Bioq.Biolog.Mol. Celular$$cÁrea Bioquímica y Biolog.Mole.
000161051 773__ $$g145, 3 (2025), 109150 [14 pp.]$$pMol. genet. metab.$$tMolecular genetics and metabolism$$x1096-7192
000161051 8564_ $$s4568322$$uhttps://zaguan.unizar.es/record/161051/files/texto_completo.pdf$$yVersión publicada
000161051 8564_ $$s2318347$$uhttps://zaguan.unizar.es/record/161051/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000161051 909CO $$ooai:zaguan.unizar.es:161051$$particulos$$pdriver
000161051 951__ $$a2025-10-17-14:14:09
000161051 980__ $$aARTICLE